1. Field of the Invention
The present invention relates to a chain guide blade for a chain saw.
2. Prior Art
Usually in accordance with prior art a chain saw guide supports on one end a rotatable sprocket for guiding a cutting chain for moving rapidly around the edge of the guide. The sprocket axle is periodically greased through an access aperture in the side plates of the guide. Since the sprocket is subjected to high temperatures while it is being rotated by the high-speed travel of the chain, the grease on the axle becomes liquified due to the intensive heat and subsequently leaks away, with the result that the sprocket will soon run short of lubricant and therefore seize to the axle. Accordingly, frequent greasing has been necessary for the reliable operation during a prolonged period of time. Furthermore, foreign matter such as sawdust, soil, dirt, or water, often times permeates through spaces between the sprocket and the side plates of the guide, and tends to mix with the grease on the axle. Therefore, the axle, the sprocket, and the roller bearings disposed therebetween are susceptible to mal-functioning and damages due to the affectation of the lubricant by foreign matter.